The president of Catalan, Carles Puigdemont, has also condemned the violence.

"Today, the Spanish state has written a shameful page in its history with Catalonia," he said at a press conference.

In Madrid, people have gathered in the Plaza del Sol to show their solidarity with the people of Catalan.

Augusto Delkader, a political analyst who was at the march at the Plaza del Sol, said he was outraged by the response to the referendum.

"The actions of the police have been totally disproportionate. They explicitly violate the fundamental right to meet freely, to protest, to free speech, free association and political participation," Delkader told teleSUR.

"The Spanish government has only offered a violent and judicial response to what is a political problem," he added.

"The Plaza de Sol in Madrid is filled with people against Rajoy's repression, who made a grave error in trying to isolate Catalonia on its referendum day."

As Spanish police wielded batons and fired rubber bullets at crowds attempting to vote in Catalonia's banned independence referendum, the region's own police force gave many voters a much gentler reception.

In Catalonia's pro-independence heartland, among the farming towns of Osona county north of Barcelona, the Catalan force made little attempt to remove people from polling stations despite being tasked with the same court order to shut them down.

Local courts received several complaints on Sunday against the Catalan police accusing them of inactivity and failing to close polling stations, despite the court order, the region's High Court said in a statement.

U.K. labor leader Jeremy Corbyn called the state violence, "shocking" and urged "the Spanish government must act to end it (violence) now."

Julian Assange also condemned the Spain's violent and repressive streak over its citizens, asking the president of the EU Commission to "suspend Spain from the European Union for its clear violation of Article 2."